clang  9.0.0svn
SymExpr.h
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1 //===- SymExpr.h - Management of Symbolic Values ----------------*- C++ -*-===//
2 //
3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4 // See https://llvm.org/LICENSE.txt for license information.
5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6 //
7 //===----------------------------------------------------------------------===//
8 //
9 // This file defines SymExpr and SymbolData.
10 //
11 //===----------------------------------------------------------------------===//
12 
13 #ifndef LLVM_CLANG_STATICANALYZER_CORE_PATHSENSITIVE_SYMEXPR_H
14 #define LLVM_CLANG_STATICANALYZER_CORE_PATHSENSITIVE_SYMEXPR_H
15 
16 #include "clang/AST/Type.h"
17 #include "clang/Basic/LLVM.h"
18 #include "llvm/ADT/FoldingSet.h"
19 #include "llvm/ADT/SmallVector.h"
20 #include <cassert>
21 
22 namespace clang {
23 namespace ento {
24 
25 class MemRegion;
26 
27 /// Symbolic value. These values used to capture symbolic execution of
28 /// the program.
29 class SymExpr : public llvm::FoldingSetNode {
30  virtual void anchor();
31 
32 public:
33  enum Kind {
34 #define SYMBOL(Id, Parent) Id##Kind,
35 #define SYMBOL_RANGE(Id, First, Last) BEGIN_##Id = First, END_##Id = Last,
36 #include "clang/StaticAnalyzer/Core/PathSensitive/Symbols.def"
37  };
38 
39 private:
40  Kind K;
41 
42 protected:
43  SymExpr(Kind k) : K(k) {}
44 
45  static bool isValidTypeForSymbol(QualType T) {
46  // FIXME: Depending on whether we choose to deprecate structural symbols,
47  // this may become much stricter.
48  return !T.isNull() && !T->isVoidType();
49  }
50 
51  mutable unsigned Complexity = 0;
52 
53 public:
54  virtual ~SymExpr() = default;
55 
56  Kind getKind() const { return K; }
57 
58  virtual void dump() const;
59 
60  virtual void dumpToStream(raw_ostream &os) const {}
61 
62  virtual QualType getType() const = 0;
63  virtual void Profile(llvm::FoldingSetNodeID &profile) = 0;
64 
65  /// Iterator over symbols that the current symbol depends on.
66  ///
67  /// For SymbolData, it's the symbol itself; for expressions, it's the
68  /// expression symbol and all the operands in it. Note, SymbolDerived is
69  /// treated as SymbolData - the iterator will NOT visit the parent region.
72 
73  void expand();
74 
75  public:
76  symbol_iterator() = default;
77  symbol_iterator(const SymExpr *SE);
78 
80  const SymExpr *operator*();
81 
82  bool operator==(const symbol_iterator &X) const;
83  bool operator!=(const symbol_iterator &X) const;
84  };
85 
86  symbol_iterator symbol_begin() const { return symbol_iterator(this); }
88 
89  virtual unsigned computeComplexity() const = 0;
90 
91  /// Find the region from which this symbol originates.
92  ///
93  /// Whenever the symbol was constructed to denote an unknown value of
94  /// a certain memory region, return this region. This method
95  /// allows checkers to make decisions depending on the origin of the symbol.
96  /// Symbol classes for which the origin region is known include
97  /// SymbolRegionValue which denotes the value of the region before
98  /// the beginning of the analysis, and SymbolDerived which denotes the value
99  /// of a certain memory region after its super region (a memory space or
100  /// a larger record region) is default-bound with a certain symbol.
101  virtual const MemRegion *getOriginRegion() const { return nullptr; }
102 };
103 
104 inline raw_ostream &operator<<(raw_ostream &os,
105  const clang::ento::SymExpr *SE) {
106  SE->dumpToStream(os);
107  return os;
108 }
109 
110 using SymbolRef = const SymExpr *;
112 using SymbolID = unsigned;
113 
114 /// A symbol representing data which can be stored in a memory location
115 /// (region).
116 class SymbolData : public SymExpr {
117  const SymbolID Sym;
118 
119  void anchor() override;
120 
121 protected:
122  SymbolData(Kind k, SymbolID sym) : SymExpr(k), Sym(sym) {
123  assert(classof(this));
124  }
125 
126 public:
127  ~SymbolData() override = default;
128 
129  SymbolID getSymbolID() const { return Sym; }
130 
131  unsigned computeComplexity() const override {
132  return 1;
133  };
134 
135  // Implement isa<T> support.
136  static inline bool classof(const SymExpr *SE) {
137  Kind k = SE->getKind();
138  return k >= BEGIN_SYMBOLS && k <= END_SYMBOLS;
139  }
140 };
141 
142 } // namespace ento
143 } // namespace clang
144 
145 #endif // LLVM_CLANG_STATICANALYZER_CORE_PATHSENSITIVE_SYMEXPR_H
A (possibly-)qualified type.
Definition: Type.h:639
MemRegion - The root abstract class for all memory regions.
Definition: MemRegion.h:94
C Language Family Type Representation.
bool operator!=(const symbol_iterator &X) const
virtual unsigned computeComplexity() const =0
virtual void dump() const
virtual const MemRegion * getOriginRegion() const
Find the region from which this symbol originates.
Definition: SymExpr.h:101
Symbolic value.
Definition: SymExpr.h:29
symbol_iterator symbol_begin() const
Definition: SymExpr.h:86
unsigned Complexity
Definition: SymExpr.h:51
virtual void dumpToStream(raw_ostream &os) const
Definition: SymExpr.h:60
Forward-declares and imports various common LLVM datatypes that clang wants to use unqualified...
virtual QualType getType() const =0
virtual ~SymExpr()=default
SymbolID getSymbolID() const
Definition: SymExpr.h:129
static bool classof(const SymExpr *SE)
Definition: SymExpr.h:136
bool isNull() const
Return true if this QualType doesn&#39;t point to a type yet.
Definition: Type.h:704
Kind
unsigned computeComplexity() const override
Definition: SymExpr.h:131
virtual void Profile(llvm::FoldingSetNodeID &profile)=0
static bool isValidTypeForSymbol(QualType T)
Definition: SymExpr.h:45
Dataflow Directional Tag Classes.
raw_ostream & operator<<(raw_ostream &Out, const CheckerBase &Checker)
Dump checker name to stream.
Definition: Checker.cpp:35
static symbol_iterator symbol_end()
Definition: SymExpr.h:87
SymbolData(Kind k, SymbolID sym)
Definition: SymExpr.h:122
static bool classof(const OMPClause *T)
Kind getKind() const
Definition: SymExpr.h:56
X
Add a minimal nested name specifier fixit hint to allow lookup of a tag name from an outer enclosing ...
Definition: SemaDecl.cpp:14051
unsigned SymbolID
Definition: SymExpr.h:112
bool isVoidType() const
Definition: Type.h:6560
bool operator==(const symbol_iterator &X) const
A symbol representing data which can be stored in a memory location (region).
Definition: SymExpr.h:116
Iterator over symbols that the current symbol depends on.
Definition: SymExpr.h:70